// Muduo - A reactor-based C++ network library for Linux
// Copyright (c) 2010, Shuo Chen.  All rights reserved.
// http://code.google.com/p/muduo/
//
// Redistribution and use in source and binary forms, with or without
// modification, are permitted provided that the following conditions
// are met:
//
//   * Redistributions of source code must retain the above copyright
// notice, this list of conditions and the following disclaimer.
//   * Redistributions in binary form must reproduce the above copyright
// notice, this list of conditions and the following disclaimer in the
// documentation and/or other materials provided with the distribution.
//   * Neither the name of Shuo Chen nor the names of other contributors
// may be used to endorse or promote products derived from this software
// without specific prior written permission.
//
// THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
// "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
// LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
// A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
// OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
// SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
// LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
// DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
// THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
// (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
// OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.


#ifndef CLUSNET_BASE_WEAKCALLBACK_H
#define CLUSNET_BASE_WEAKCALLBACK_H

#include <functional>
#include <memory>

namespace clusnet
{
namespace base
{

template<typename CLASS, typename... ARGS>
class WeakCallback final
{
    public:
        WeakCallback(const std::weak_ptr<CLASS>& object, const std::function<void (CLASS*, ARGS...)>& function)
            : object_(object), function_(function)
        {
        }
        WeakCallback(const WeakCallback&) = default;
        WeakCallback(WeakCallback&&) = default;
        WeakCallback& operator= (const WeakCallback&) = default;
        WeakCallback& operator= (WeakCallback&&) = default;
        ~WeakCallback() = default;

        void operator()(ARGS&&... args) const
        {
            std::shared_ptr<CLASS> ptr(object_.lock());
            if (ptr)
            {
                function_(ptr.get(), std::forward<ARGS>(args)...);
            }
        }

    private:
        std::weak_ptr<CLASS>    object_;
        std::function<void (CLASS*, ARGS...)>   function_;
};

template<typename CLASS, typename... ARGS>
WeakCallback<CLASS, ARGS...> makeWeakCallback(const std::shared_ptr<CLASS>& object, void (CLASS::*function)(ARGS...))
{
    return WeakCallback<CLASS, ARGS...>(object, function);
}

template<typename CLASS, typename... ARGS>
WeakCallback<CLASS, ARGS...> makeWeakCallback(const std::shared_ptr<CLASS>& object, void (CLASS::*function)(ARGS...) const)
{
    return WeakCallback<CLASS, ARGS...>(object, function);
}

}
}
#endif 
